The secant of x, $\sec x$, is the reciprocal of the cosine of x, so $\sec x = \frac{1}{\cos x}$. The tangent of x, $\tan x$, is the ratio of the sine of x to the cosine of x, so $\tan x = \frac{\sin x}{\cos x}$. Therefore, we can rewrite the right hand side of the
Show more…
